1. Field of the Invention
This invention relates to improved hollow cases for enclosing substrates, especially cable splices.
The cases of the invention are particularly useful for enclosing splices between multi-pair telephone cables, and will be described chiefly by reference to such use. It is to be understood, however, that the invention is not limited to such use.
2. Description of the Prior Art
The function of a splice case is to provide environmental protection for the splice. For this purpose it must remain sealed around the cables in spite of variations in the difference in gaseous pressure between the inside and outside of the case, which can be substantial. In non-pressurized cable systems, such variations will cause the internal pressure sometimes to be less and sometimes to be more than the external pressure. Even in pressurized cable systems, in which positive gaseous pressure is normally maintained within the cable, the external pressure can sometimes exceed the internal pressure. The known splice cases all suffer from one or more serious disadvantages, and the present invention provides a novel splice case which alleviates or removes one or more of those disadvantages.
Thus the two methods at present most widely used to encase splices in pressurized telephone cable systems employ soldered lead sleeves (whose installation requires a great deal of skill and time) or cases which are bolted together and sealed with mastic (whose installation requires the careful assembly of many pieces, taking care to ensure that the bolts are properly torqued and that the correct amount of mastic is employed). Particular types of splice case are described in German Pat. Nos. 1,908,996 and 1,966,933, U.S. Pat. Nos. 3,678,174, 3,663,740 and 3,576,937; and German OLS No. 2,158,992.